1. Technical Field
An aspect of the present invention relates to an image forming apparatus, specifically to an image forming apparatus having an image forming unit and a belt unit with a seamless belt.
2. Related Art
An image forming apparatus having a belt unit and an image forming unit with a colorant (e.g., toner) container is known. The belt unit may include a driving roller, a driven roller, and a seamless belt to roll around the driving and driven rollers. The seamless belt may be rolled to convey a transfer medium (e.g., a sheet of paper) on a surface thereof, and an image formed in the image forming unit may be transferred onto the sheet when the sheet being conveyed on the belt comes to a position to face the image forming unit.
In this regard, quality of the image appearing on the transfer medium can be affected by various factors, such as timing of the image transfer on the transfer medium and condition of the belt rolling in the belt unit. Therefore, in order to maintain desired imaging quality, it is preferred that the surface of the belt is maintained flat and straightened at least at the part, which faces the image forming unit.
In order to maintain the straightened surface of the belt, the belt unit may have a compression spring in vicinity of the driven roller, which presses the driven roller outward in a direction to be away from the driving roller, so that the belt rolling around the driving roller and the driven roller is tensely stretched outward.